Progressively-burning powder and proccess of making the same



PANY,

RICHARD o; w'oonrcztioon, sense-es n. CASEY, nn assesses or wimvrmo'ron, DELA'WARE, .assienoes TO n. DU rorrr DE meanness cors- PRC GRESSIVELY-BUBHENG POVJIOEB. AND PROCESS OF MAKING" SAlVIE.

No Drawing.

' siFvely-Bnrning Powder and T' ocess of Mal:-

ing" the Same of which the spec] icatlon.

This invention relates to propellcnt powfollow is ders which have been provided with a detorrent material to retard their rate of coinbustion; and it comprises a powder of this typecoated with an easily ignitihlc propellant, and a process of making such powder.

ll hile all smokeless ,propellent powders are progressive burningothe terni Progressive burning powders has in recent years been applied to powders of the surface treated type which are extensively used in military rifles. In powder of this type the burning of the powder grain is regulated by treating, the surface of the powder grain with a deterrent material such as an explosive, or nonexplosive, deterrent, or a mixture of these, thereby causing the outer layer of the powder to burn more slowly, which results inreduced pressure at, the breech of the gun and does not unduly increase the pressure along the bore of the rule. As

might be expectcd,surface treated powders are more dnlicult to ignite than non-surface treated powders but this dillicnlty "in iggn'tion has been largely overcome by the use of decidedly stronger primers. Thus, by the use of decidedly stronger primers for the ignition of surface treated powders, ballistic results-have been. obtained much in advance over ballistic results obtainable from non-surface treated powders. in view of this fact that surface treated powders have been used quite successfully in this manner. it had not been realized that greater possibilities existed in connection with the use of pmvdor of this type.

lu seeking to overcome ignition, it to incorporate in the smokeless powder charge a supplementary priming charge composed preferably of this difiicnlty in Specification of Letters Patent. Tai gater med Slept, 2f}, 19/ @c has been proposed by one of as black powder, either. by m xing it with the smokeless powder or Application filed February 25, 1820. Serial No. 361,287.

less powder, there is a tendency for the black powder to segr gate upon handling or shipment, especr when the larger size nitrocellulose grains aroused. If the black powder is placed at the base of the shell, two

the shell, and there is liability or" a Variation in the amount of black powder added to different shells. i

A line of attack on this problem which appeared promising lay in coating the chilicultly ignitible progressive burning powder with an easily ignitible propellant; Previous experiments in this connection had in dicated that difi iculty would probably be encountered in causing an easily ignitible propellant, such as black so strongly that dusting of the black powder would not occur during handling of the coated. grains, this dusting (that is, forrnm tion of black powder'dust) being liable to lead to premature explosions. We have now easily L} iitible propellant, and a substan L1 tially non-volatile binds:

he nitrocellulose ably both solvent for and an explosive.

Our invention may be described in greater detrlil follows The smokeless powdecgrains to which a SZOZttlHQ; of black powder is applied accord-v ing' to our invention may be made accordloading operations are required for filling powder, to adhere ing to the usual methods of manufacture. I

For example, sutiicient nitrocellulose to give 100 lbs. by weight of nitrocellulose, which may be a mixture of nitrocellulose soluble in ether-alcohol, with nitrocellulose relatively insoluble in ether-alcohol, or may be soluble nitrocellulose alone, is dehydrated with ethyl alcohol of approximately strength by volume by means of agdehydreting press in order to displace the water. The excess alcohol is removed fronithe ni trocellulose, leaving about 33%; parts, by

weight, of alcohol in the dehydrated nitrowith brine lulose and solvent in themixer there may der composition'by atile solvent for cellulose. To this is added approximately 66% parts by, weight of ethyl ether in a suitable mixing machine, preferably provided refrigeration. To the -nitrocelbe added one-half or more parts of diphenylamin or other stabilizer, together with graphite, powdered metals, nitrocompounds,

etc., in varying amounts. The composition isthoroughly mixed and colloided, which operation in the mixer requires about one half hour or more, depending 011 the efficiency of the mixer. After thoroughly mixing, the colloided composition is formed into preliminary blocks by means of a press. These blocks are then pressed in the so called finishing press and the composition pressed through dies into strings, which strings are granulated by means of a cutting machine. The granulated powder is then placed for one or more days in solvent recovery apparatus to recover the alcohol and ether, and then dried in water or air to reduce the solvent remaining in-the powder to a low amount.

The powder may, if desired, then be surface coated with a deterrent, such as dimethyldiphenylurea, or anexplosive deterrent, such as dinitrotoluene, or a mixture of these or other explosive or non-explosive deterrents, according to the process described in Patent 1,310,848 to O. J. Teeple, Jr., 1,313,459 to'A. L. Broadbent and R. VVoodbridge, Jr., or 1,312,463 to R. G. Woodbridge, Jr.

Smokeless manufactured asabove and whose surfaces have been treated with a deterrent material or a deterrent explosive or a mixture of these or other deterrent materials or deterrent explosives, are then, in accordance with our invention, surface coated with a black powa process such as that illustrated in the following example 100 parts of the above described smokeless powder grains are mixed in a revolving drum with 1 to 10 parts of a black powder composition and about 2 parts of a non-vol nitro-cellulose, such as dinitrotoluene. The dinitrotoluene may be any one of several isomersor a mixture of the same obtained by the direct nitration of toluene, but we prefer to use pure dinitrotoluene 2'. 0., L2 1.dinitrotoluene. After the materials in the drum have been thoroughly mixed, 6., in from 5 to 10 minutes, heat is applied in any suitable mannerto the outside of the drum or to the jacket of the drum if so provided. until the mixture of powder grains. black powder and dinitrotoluene is heated to a temperature slightly above the melting point of the dinitrotoluwe. In the case of the l2-l dinitrotoluene derivative a temperature of 70 to C. is usually sufficient, depending upon the black powder grains which have been it colloids with the nitrocellulose of the sur-,

face of the"powder grains and impregnates the surface to a substantial distance while powder composition becomes firmly attached to the surface of the powder grains partly as an exterior coating but also at the same time and to a considerable extent is carried into the pores of the nitrocellulose colloid. In this manner the black powder composition is so firmly attached to the smokeless powder grains that it is essentially arr-integral part of the powder and cannot be removed without destroying the powder grainslg lVe do not limit ourselves to the use for every 100 parts of powder grains of 1 to 10 parts of black powder composition and 2 parts of dinitrotoluene or other non-volatile solvent for nitrocellulose, as it is clear that we can vary the amount of black powder mixture and percentage of dinitrotoluene contained therein according to the ballistics desired.

In place of dinitrotoluene we may use other non-volatile nitrobenzenoid hydrocarbons such as dinitrobenzene, monoor tri-nitrotoluene, and monoor poly-nitroxylenes; or other nitroaromatic hydrocarbons, as for example mono-nitronaphthalene; or aromatic amids such as phenylacetanilide and dimethyldiphenylurea, provided the sub stance to be used is a solvent to some extent for nitrocellulose. In the case of non-volatile solvents with a relatively high melting point, such as dimethyldiphenylurea, which has a melting point of 120 to 121 (1., when pure, we prefer to add to this 25% or more of dinitrotoluene in order to obtain a'mixture with a melting point considerably below 100 C.

lVhile we prefer to use "a non-volatile solvent for nitrocellulose as a binding agent for the easily ignitible explosive, we may also use other binding agents such as diphenylamin, rosin, etc. which, though not solvents from nitrocellulose, can be melted at a temperature which has no injurious effect on the stability of the powder.

The black powder which we prefer to use is of the composition generally used for black sporting powder and of approximately the following composition: 74.0% saltpe- ,ter, 10.4% sulphur, 15.6% charcoal.

ill

'jurious effect on the star less powder grail our process Ell'w ustmt Nitrocellulose powder pared from :1 mixture of soluble and grains were preinsoluble nitrocellulose and surface treated with 6 parts of diinethyldiphenylurea per 100 parts of powder. This powder before being treated with black powder composition according to our invention above described gave in the 30/06 Springfie d rifle with l-grain bullet using a weight of ch rge of 55.0 grains, a mean instrumental velocity at 78 ft. of 2,572 feet per second, with a mean pressure oi 32 ,350 pounds, lhis pow der was diilicnlt of a, dnc to the considerable amount of dinierlhyldiphenylurea with which one surface of the powder grains hurl been treated. A. portion of the same powder grains was tresn in (3 parts of a.. mixture composed of or". black powder composition and l linitrot'oluenc, according to our invention as abore described. The poi 'der grains so treated were found to be more readily ignite and with a, grains weight oi char e gave in the .30/06 Sm'ingticld rifle, with lilo-grain bullet, a mean instrljnnental velocity at 78 it. of 2,458 feet per second, with a mean pressure of only 2?,4190 lbs.

We claim 1. The process of coating dete rent-carry ing .itrocellnlose powde= t eas ly ignitibl propell mixing said grains and en the pr sence of a nonvo [.Il binr meltable at a tcmperatx :1 while heating the mass a slightly almre the melting point ing i 2. The process or coatin ing n trocellulose powoc easilv 'itibl grains and c of it nonwole at a terngwrnlnre on the stobil'ty ing the mass to a t the melting point of 3. The process ol 4 ing nitrocellulose powder s asily ignitible propell t comprising s-,- sium nitrate, which mixing said grains and said propellant in the presence of a nonvolatile binding zneltable, at a temperature that has no injurious ei'lcct on of the powder and capable,

" li nitrocellulose, a temperature the bindv H s M 1 mg n i A'illliilS-ifi powder ginnis easily innit pron t, whim.

, meltable at a ing nitrocellulose powder grains with black powder which comprises mixing 100 parts of said grains with from 1 to 10 parts of a. black powder composition containing about 20']; of dinitrotolnene, while heating the mixture to a temperature slightly above the point of the clinitrotoluene.

6. Si propellent powder comprising deterrent-carrying nitrocellulose powder grains having a. firmly adherent coating of an easily ignitible propellant.

4". A propcllent powder comprising deterrent-carrying nitrocellulose powder grains having a firmly adherent coating of an easily igni tible propellant compi rising potassium nitrate.

9 A propellent powder comprising deterrent carry'ing nitrocellulose powder grains and an easily ignitible propellant held to said grains by a non-volatile binding agent ineltable at a temperature that has no injurious eliect on the stability of the powder A propellent powder comprising deterrent-carrying nitrocellulose powder grains and an easily ignitible propellant held to said grains by a non-volatile binding agent temperature that has no in- 511310135 e'll'ect on the stability of the powder, and capable, when melted, of dissolving nitrocellnlose.

10 A. propellent powder comprising deterrentcnrrying nitrocellulose powder grains and an easily ignitible propellant held to said grains by a nonvolatile nitrocellulosesolvent which is itself an explosive.

ll. A propollent powder comprising deterrent-carrying nitrocellulose powder grains and an easily ignitihle propellant comprisg potsissiinn nitrate held to said grains by n temg iereture that has no injurious effect on re stability of the powder, and capable, when melted, of dissolving nitrocellulose.

r2. A propellent powder comprising deterrent-mrrying nitrocellulose powder grains having a coating 0t black powder held to the surface of the grains by an aromatic nitro-hydrocarbon capable of forming a colloidal solution with nitrocellulose.

13. A propellent powder comprising deterrent-carrying nitrocellulose powder grains having a coating of black powder held to the surface of the grains by a nitro-benzenoid hydrocarbon.

1 A propellcnt powder comprising deterrent-carrying nitrocellulose powder grains having a coating oi black powder held to the surface of the grains by a dinitro-benzenoid hydrocarbon.

15. A i'ooel ent aowder corn )risirw ileul" n *nvolatile binding agent inelteble at 10 parts of black powder held to the surface rent-carrying nitrocellulose powder grains having a coating of black powder held to the surface of the grains by dinitrotoluene.

16. A propellent powder comprising deterrent-carrying nitrocellulose powder grains having a coating of black powder held to the surface of the grains by substantially pure 1 2,4-dinitrotoluene.

17. A propellent powder comprising deterrent-carrying. nitrocellulose powder grains having a coating of black powder consisting of75 parts of potassium nitrate, about 10 parts of sulfur, and about 15 parts of charcoal held to the surface of the grains by an aromatic nitro hydrocarbon capable of forming a colloidal solution with nitrocellulose.

18. A propellent powder comprising 100 parts of nitrocellulose powder grains carrying sufficient deterrent material to render them difficult to ignite, and from about 1 to of said grains by a non-volatile solvent for nitrocellulose.

' 19. A propellent powder comprising 100 of said grains by a binding agent comprising an aromatic nitro-hydrocarbon capable of forming a colloidal solution with nitrocellulose.

' 20. A propellent powder comprising 100 parts of nitrocellulose powder grains carrying sufi'icient deterrent material to render them difficult to ignite, and from about 1 to 10 parts of black powder held to the surface .of said grains by dinitrotoluene.

In testimony whereof we affix our signa- 40 tures.

RICHARD G. WOODBRIDGE, JR. KELLOGG K. V. CASEY. CLARENCE I. B. HENNING. 

